Fastening dissimilar materials has proven challenging. Friction stir welding allows for the joining of dissimilar metals, but the torque required to hold the materials in place so they do not spin is quite high. That is why most friction stir welding applications involve flat parts or parts with flat contours. More complicated parts such as those used in the automotive industry require more extensive clamping. Further, friction stir welding does not completely support the joining of some dissimilar metals, such as steel and magnesium or steel and titanium, or metals to plastics or composite materials. Instead, adhesives or rivets are used. However, adhesives are typically weaker than the materials being joined and rivets are susceptible to fatigue fractures and galvanic corrosion, making them unsuitable for joining dissimilar materials for use in high stress applications.